Another Boeing 787 engine problem—this time involving a General Electric GEnx turbofan in an airplane destined for Air India—sparked a grass fire at Charleston International Airport during a pre-flight test on Saturday, forcing the airport to close its main runway for more than an hour. The contained engine failure has prompted an investigation by the NTSB, Boeing and GE, maker of the engine now in service with Japan Airlines on four 787s.

Evidence so far points to a failure in the “back end” of the engine, specifically in the area of the low-pressure turbine. “GE Aviation continues to work with the NTSB and Boeing to determine the cause of Saturday’s incident during a ground-test run in Charleston on a newly built 787,” said the engine company in a statement sent to AIN. “GE is working aggressively to move the engine involved in the incident to a GE facility for an investigative tear-down.”

The incident involved the second of three 787s that have rolled off Boeing’s new assembly line in Charleston, South Carolina. It came roughly a week after Japan’s All Nippon Airways had to ground its five Rolls-Royce Trent 1000-powered 787s following the manufacturer’s discovery of corrosion in a crown gear within an external gearbox during product development testing.

ANA has since returned four of its five airplanes to service, and plans to redeploy the fifth early this week.